"Often the murderer has no previous acquaintance with, or knowledge of, the man whom he kills. He blindly obeys the command of his infernal order, and is thus made a tool to avenge some petty grievance or fancied injury. "The Mollies have become a plague-spot that threatens the health and life of this region. It is the duty of every honest man and boy who is brought into any sort of contact with them to thwart their evil designs in every possible way." "Well," said Derrick, drawing a long breath, "I had no idea that there were such wicked men in this country." "No," he answered the mine boss, "you are but a boy, and have had but little experience in the wickedness of this world; but I know you are brave, and I believe you to be honest and loyal. I am therefore going to trust you, and tell you something that I had no intention of mentioning when I sent for you this evening. It is this: "I have every reason to believe the Mollies are strong in this colliery, and that they intend to make trouble here. I have lately received several anonymous letters making demands that cannot possibly be granted, and containing vague threats of what will happen in case they are not satisfied. This morning I found this note pinned to my door." Here Mr. Jones opened a drawer of his desk, and took from it a dirty sheet of paper, which he handed to Derrick. On it was scrawled the following: "Bosses take Wornin'. New breakers can burn as well as old. Fires cost munny. Better pay it in wage to "MOLLIE." As the boy finished reading this strange communication which was at the same time an admission and a threat, he looked up in surprise and began, "Then you think, sir--" "Yes," interrupted the mine boss. "I not only think, but I feel convinced, that the mischief has begun. Moreover, I am determined that it shall end before it goes any further. I am most anxious to discover who is at the bottom of it, and in this I want you to help me." "Want _me_ to help!" exclaimed Derrick, in astonishment. "Yes, you," answered Mr. Jones, smiling. "Your very youth and inexperience will render you less likely to be suspected than an older person. I am certain that I can count upon the son of my old friend Gilbert Sterling to perform truly and faithfully any duty which his employers may see fit to intrust him with. Is it not so, Derrick?" "Yes, sir, it is," cried the boy. "Just tell me what you want me to do, and if I don't succeed it won't be because I haven't tried my best." "That is just what I expected you to say," remarked the mine boss, quietly. "Now we will lay our first plans. I suppose you have had enough of the breaker, haven't you?" "Indeed I have, sir." "Very well. For a change I am going to offer you a job in the mine where I will give you a bumping-mule to drive. Your wages will be five dollars a week."